Lipophosphonoglycan, a polymeric glycosphingolipid that comprises about 30 percent of the plasma membrane of Acanthamoeba castellanii, contains two subunits that can be separated on analytical dodecyl sulfate polyacrylamide electrophoretic gels. We have now developed a preparative procedure for separating the two components by chromatography on polyacrylamide columns in sodium dodecyl sulfate.